1. Field of the Invention
The present invention relates to electronic and mechanical devices for recording doses of pre-measured, aerosol-delivered prescription and over-the-counter medication released from a pressurized canister contained in a patient-held dispensing unit. The invention is used in conjunction with conventional aerosol medication dispensing devices and is also used for the purpose of keeping an accounting of the number of doses dispensed from the pressurized canister. This method of medication delivery is utilized to treat and control asthma and other respiratory diseases afflicting approximately eleven million adults and children.
2. Description of the Related Art
It is of absolute necessity to keep an accurate record of the number of medication doses dispensed from a pressurized canister in order not to exceed the number of safe doses indicated by a manufacturer. Exceeding a manufacturer's indicated safe dose rapidly increases the potential for prematurely running out of the actual medication in the canister, and eventually dispensing only the remaining propellant. This unexpected depletion of medication can lead to either an aggravation of the disease symptoms, an increased need for medication, or, in extreme cases, hospitalization to bring the disease under control. Conversely, an overly cautiously approach to the number of the manufacturer's indicated safe doses by prematurely throwing away the canister before the medication is actually used up results in an increase in costs for the patient due to the waste of the remaining safe doses in the medication canister.
There is a general lack of knowledge among patients and health care professionals concerning pressurized medication dispensers and their limitations. Uninformed patients shake the canister and listen to the sound of the liquified gas propellant which may not contain the proper amount of medication in suspension for a prescribed dose. Others spray in the air to observe the mist which may be deficient in medication, while others just guess. Informed patients utilize manual recording of each use and/or calculate the date and time of day when the last fully safe dose is reached.
The latter method is complicated and prone to error, as some medications are used on demand (i.e., before athletic activity or at the onset of disease symptoms). The same or other medications may be utilized as a doctor directs at pre-determined intervals which may change over the life cycle of the pressurized medication canister. Many patients are often on more than one medication delivered at different time intervals which can further complicate the counting process.
Thus, it is a problem in the prior art to provide the patient with an accurate count of the safe doses remaining in a metered and pressurized medication canister.
It is also a problem in the prior art to provide the patient with a visual warning about the impending and final exhaustion of the manufacturer's designated "safe" limit of medication doses contained within a metered and pressurized canister.